Synthesis and characterization of Ag–TiO2–CNT nanoparticle composites with high photocatalytic activity under artificial light

Carbon nanotube (CNT)-modified silver titania (Ag–TiO2) nanoparticle composites were synthesized by photochemical reduction. Characterization of the composites was performed using field emission-scanning electron microscopy (FE-SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), and Raman spectroscopy. It was found that TiO2 particles were uniformly distributed on CNTs, and the silver particles were decorated on the surface of the TiO2. The photocatalytic activity of Ag–TiO2–CNT nanoparticle composites synthesized with various concentrations of CNTs was investigated using methylene blue (MB) dye solution. Adsorption and recovery of MB showed that Ag–TiO2–CNT nanoparticle composites have a higher absorption efficiency than unadorned CNTs. The higher absorption demonstrates a synergistic effect between the CNTs and silver titania. Overall, novel photocatalytic nanoparticle composites that adsorb organic molecules, absorb light energy, and separate long-lived electron–hole pairs through spatial separation were developed. Minimization of electron–hole recombination allows efficient transfer of photochemical energy which affects the redox chemistry across the interfaces in the composites. The new composites were designed for environmental cleanup of organic pollutants.